The present invention relates generally to nanolithography and specifically to a polymer electrostatic nanolithography method using Atomic Force Microscopy.
The use of nano and micro-scale structuring of polymers, whether as a sacrificial, pattern-transfer layer or as the active component in a nano-device, is integral to nearly every aspect of future material fabrication. Two general areas of interest are polymer patterning for micro/nanofabrication and ultra dense data storage. Ultra compact data storage in thin polymer films is a promising alternative to sometimes unreliable ferromagnetic storage mediums such as computer floppy disks and the like.
Recent nanolithography investigations to date are based on the spatially selective removal or deposition of polymer. While somewhat successful, the prior art techniques are generally slow to perform. These techniques generally require chemical cross-linking, and/or substantial polymer degradation or ablation to effect. This permanently changes the composition and structure of the media itself, rendering it ineffective for repetitive data storage and retrieval applications.
A recent polymer nanolithography technique is described in U.S. Pat. No. 6,249,747 to Binning et al. The Binning device utilizes a cantilevered tip within an Atomic Force Microscope wherein an electrically conductive material is attached to the tip. In use, an electric current is applied to the electrically conductive material, creating heat within the tip. The tip, thus heated, is selectively applied to a heat deformable film to create pits. The pits are utilized to convey information by the creation of a coherent structure. This information is binary (pits, smooth surface). While this technique is somewhat effective, it has the disadvantage that a specialized tip is required and the application of current to heat the tip slows the overall lithographic process.
A need exists therefore for a high speed polymer nanolithography method that facilitates rapid polymer feature creation without polymer degradation, cross-linking or removal. Such a method would enable reliable, high speed feature creation, and additionally provide for a ready erasure process and subsequent re-patterning of the polymer film. Such a method would desirably impart additional information beyond binary by the creation of raised areas in addition to pits and smooth surface.